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Re: Will redeploying webserver and scheduler in Kubernetes cluster kill running tasks


Hey Kyle, the task pods will continue to run even if you reboot the
scheduler and webserver and the status does get updated in the airflow db,
which is great.

I know the scheduler subscribes to the Kubernetes watch API to get an event
stream of pods completing and it keeps a checkpoint so it can resubscribe
when it comes back up.

I forget if the worker pods update the db or if the scheduler is doing
that, but it should work out.

On Thu, Aug 30, 2018, 9:54 AM Kyle Hamlin <hamlin.kn@xxxxxxxxx> wrote:

> gentle bump
>
> On Wed, Aug 22, 2018 at 5:12 PM Kyle Hamlin <hamlin.kn@xxxxxxxxx> wrote:
>
> > I'm about to make the switch to Kubernetes with Airflow, but am wondering
> > what happens when my CI/CD pipeline redeploys the webserver and scheduler
> > and there are still long-running tasks (pods). My intuition is that since
> > the database hold all state and the tasks are in charge of updating their
> > own state, and the UI only renders what it sees in the database that this
> > is not so much of a problem. To be sure, however, here are my questions:
> >
> > Will task pods continue to run?
> > Can task pods continue to poll the external system they are running tasks
> > on while being "headless"?
> > Can the tasks pods change/update state in the database while being
> > "headless"?
> > Will the UI/Scheduler still be aware of the tasks (pods) once they are
> > live again?
> >
> > Is there anything else the might cause issues when deploying while tasks
> > (pods) are running that I'm not thinking of here?
> >
> > Kyle Hamlin
> >
>
>
> --
> Kyle Hamlin
>